Optical diffusers and optical lenses can be used in various applications to disperse light emitted from a light source across an area to evenly light an object. A measure of an article's ability to act as a diffuser can be the Degree of Light Dispersion (DLD) value which measures the difference between the coherent transmission and the diffusive transmission of light passing through the article at a fixed transmittance. These diffusers and lenses can be used in a wide variety of applications including mobile phones, computer monitors, televisions and other display screens, light bulbs, and any lighting device where light dispersion is desired.
Optical diffusers and lenses can be made of glass which can include colorants and/or surface treatments to improve their diffusive effect. Glass diffusers and lenses can offer good stiffness, and good optical diffusivity, but poor impact resistance. Even thin wall diffusers and lenses made of glass can be heavy in comparison to equivalently sized plastic articles. Using engineered plastics (EP), e.g., polycarbonate (PC) and poly(methyl methacrylate) (PMMA), to make diffusers and lenses can reduce their weight. However, these plastics can have other drawbacks. For example, PC can have poor stiffness and PMMA can have poor stiffness and low impact resistance.
Thus there remains a need for optically diffusive plastics that can be formed into thin wall optical diffusers and/or optical lenses which can have high stiffness, impact strength, and a high degree of light dispersion (DLD) value while at low weight in comparison to glass and other engineered plastics.